Use of coumarins and carbostyrils as PLA2 inhibitors, new coumarins and carbostyrils, processes for the production thereof and pharmaceutical agents

ABSTRACT

Use of compounds of formula I ##STR1## in which R 1 , R 2 , R 3 , R 4 , Y and Z have the meanings stated in the claims, tautomers thereof as well as their salts with non-toxic acids or bases for the production of pharmaceutical agents having an inhibitory action on PLA 2  in addition to compounds of formula I in which X does not denote a valency and processes for the production thereof.

This application is 371 of PCT/EP94/02251 which is now published as No.95/02588.

The present invention concerns the use of coumarins and carbostyrils asPLA₂ inhibitors, new coumarin and carbostyril derivatives, processes forthe production thereof and pharmaceutical agents which contain thesecompounds.

The invention concerns coumarin and carbostyril derivatives of thegeneral formula I ##STR2## in which R₁ denotes hydrogen or C₁ to C₆alkyl

R₂ denotes hydrogen or a residue OT₁ or

R₁ and R₂ together with the carbon atoms to which they are bound form a3-membered to 7-membered carbocyclic ring

R₃ denotes hydrogen or a residue OT₂

R₄ denotes hydrogen or C₁ to C₆ alkyl

T₁ and T₂ which can be the same or different in each case denote C₁ toC₆ alkyl, C₁ to C₆ alkanoyl or T₁ and T₂, together with the atoms towhich they are bound, form a 5-membered to 7-membered heterocyclic ringwhich can be substituted if desired with oxo or thioxo, or

R₃ and R₄ together with the carbon atoms to which they are bound form apyridine ring,

Q denotes an oxygen atom or a NH group

X denotes a valency bond, an oxygen or sulphur atom or a NH group

Y denotes a valency bond, a C₁ to C₆ alkylene residue which can besubstituted if desired with a hydroxyl group or an amino group, aphenylene residue which can be substituted if desired once or severaltimes with hydroxyl, halogen, C₁ to C₆ alkyl or carboxyl

denotes hydrogen, halogen, carboxyl, hydroxymethyl, C₁ to C₆alkoxycarbonyl, cyano or a group NR₅ R₆ in which

R₅ and R₆ which can be the same or different, each represent hydrogen orC₁ to C₆ alkyl or

R₅ and R₆ together with the nitrogen atom to which they are bound, forma 3-membered to 7-membered heterocyclic ring which can be substituted ifdesired with oxo, hydroxy or C₁ to C₆ alkoxy or contains a furtherheteroatom such as oxygen or sulphur

their tautomers as well as salts thereof with non-toxic acids or bases.

Some of the compounds of formula I are known. Thus compounds of formulaI are described in Chem. Abstr. 60, 4114b in which R₁ =R₄ =H, R₂ =R₃=OH, Q=O, X=Y=valency and Z=NR₅ R₆ as agents for the treatment ofvascular diseases. In Chem. Abstr. 84, 159773k it is stated that suchsubstances do not inhibit a carrageenin oedema.

Compounds in which R₁ =R₄ =H, R₂ and R₃ =OH or alkyl =OH, Q=O,X=valency, A=alkylene and Z=hydrogen are described for example in Chem.Abstr. 68, 76748z as inhibitors of phenylalanine hydrolase; compounds inwhich R₁ =R₄ =H, R₂ and R₃ together are methylene-dioxy or R₂ =R₃ =OCH₃,Q=O, X=Y= valency and Z= carboxyl or alkoxycarbonyl are described inChem. Abstr. 100, 31674k and 112, 151027 as fluorescent markers.

The synthesis of 4-methyl-6,7-dihydroxycoumarin is described in Chem.Ber. 34, 423 (1901). 4-Chloromethyl- 6,7-dihydroxycoumarin is known fromChem. Abstr. 60, 4113 (1964) and Beilstein 18/3 V 233.

An anti-inflammatory action or specifically a PLA₂ inhibitor is notstated.

The compounds of formula I have valuable pharmacological properties andin particular they can inhibit the activity of phospholipases. Thus theyare suitable for the treatment of acute and chronic, allergic,non-allergic and traumatic and inflammatory diseases such as for examplerheumatoid arthritis, osteoarthritis, ulcerative colitis, acutepancreatitis, contact dermatitis, inflammatory and allergic respiratorytract diseases, septic shock, allergic shock, serum sickness, autoimmunediseases, graft-versus-host reactions, host-versus graft diseases,ischaemic or thrombotic diseases, such as coronary infarction orcerebral infarction.

Aklyl residues in the said groups alkyl, alkoxy and alkanol can bestraight-chained or branched. Preferred residues are the methyl, ethyl,propyl, isopropyl, n-butyl, isobutyl, tert.-butyl, n-pentyl and 3-pentylresidue.

Alkylene residues can be straight-chained or branched. Preferredresidues are methylene, 1,2-ethylene, 1,3-propylene, 1,2-propylene and2,2-propylene.

Halogen atoms are in particular fluorine, chlorine and bromine.

Residues which enable R₁ and R₂ to together form a carbocyclic ring arepreferred:

    --CH.sub.2 --CH.sub.2 --.sub.2 --, --CH.sub.2 --CH.sub.2 --CH.sub.2 --CH.sub.2 -- or CH═CH--CH═CH--.

Residues which enable R₂ and R₃ to together form a heterocyclic ring arepreferred: ##STR3##

Residues which enable R₅ and R₆ to form a heterocyclic ring togetherwith a nitrogen atom are preferred:

    --CH.sub.2 --CH.sub.2 --CH.sub.2 --CH.sub.2, --CH.sub.2 --CH.sub.2 --CH.sub.2 --CH.sub.2 --CH.sub.2 --,

    --CH.sub.2 --CH.sub.2 --O--CH.sub.2 --CH.sub.2 --, --CH.sub.2 --CH.sub.2 --S--CH.sub.2 --CH.sub.2 --

All substances which have every possible combination of the substituentsstated in the examples are in particular a subject matter of theinvention in addition to the compounds stated in the examples.

The invention also concerns new compounds of formula I in which X doesnot represent a valency bond as well as salts thereof with non-toxicacids or bases.

The process for the production of compounds of formula I according tothe invention is characterized in that a compound of the general formulaII ##STR4## in which R₁ and R₄ and Q have the meanings stated above andR₇ represents hydrogen or a C₁ to C₆ alkanoyl residue is reacted in aknown manner with a compound of the general formula III ##STR5## inwhich X, Y and Z have the meanings stated above and R₈ represents a C₁to C₆ alkyl residue and it is cyclized,

subsequently one or several residues R₁ to R₄, X, Y or Z are optionallyconverted into another residue as defined in the claim and it isoptionally converted into a salt by neutralizing it with non-toxic acidsor bases.

It is expedient to react compounds of formula II with compounds offormula III in an acidic medium such as diluted sulphuric acid or in anon-aqueous solvent in the presence of a Lewis acid such as zincchloride or aluminium chloride while heating.

Subsequent optional conversion of one or several residues for examplemeans

cleaving an alkyl or alkanoyl residue which represents T₁ and/or T₂ byether cleavage or hydrolysis or the introduction thereof by means ofalkylation or esterification,

replacing a halogen atom representing XYZ by nucleophilic substitutionwith formation of an O--YZ, NH--YZ or S--YZ group, a CN group or a groupNR₅ R₆,

saponifying an alkoxycarbonyl or cyano group representing Z to form acarboxyl group,

esterifying a carboxyl group representing Z to form an alkoxycarbonylgroup

reducing an alkoxycarbonyl or carboxyl group to form a hydroxymethylgroup.

Compounds of formulae II and III are known from the literature or can besynthesized in a trivial manner from known precursors.

Alkaline, alkaline-earth and ammonium salts as well as salts withnon-toxic inorganic or organic acids such as hydrochloric acid,sulphuric acid, phosphoric acid, hydrobromic acid, acetic acid, lacticacid, citric acid, malic acid, benzoic acid, salicylic acid, malonicacid, maleic acid, succinic acid or diaminocaproic acid come intoparticular consideration as pharmacologically tolerated salts.

Salts are obtained in the usual way by neutralizing compounds of formulaI with appropriate lyes or acids.

For the production of pharmaceutical agents the compounds of the generalformula I are mixed in a known manner with suitable pharmaceuticalcarrier substances, aromatics, flavourings and dyes and are formed forexample into tablets or dragees or are suspended or dissolved in wateror oil such as e.g. olive oil by addition of appropriate auxiliarysubstances.

Substances of the general formula I can be administered parenterally ororally in a liquid or solid form. Water can preferably be used as theinjection medium which contains the common stabilizing agents,solubilizers and/or buffers for injection solutions. Such additives arefor example tartrate or borate buffer, ethanol, dimethyl-sulfoxide,complexing agents (such as ethylene-diamine tetraacetic acid), highmolecular polymers (such as liquid polyethylene oxide) to regulateviscosity or polyethylene derivatives of sorbitan hydrides.

Solid carriers are for example starch, lactose, mannitol,methylcellulose, talcum, highly dispersed silicic acid, higher molecularpolymers (such as polyethylene glycols).

Preparations which are suitable for oral application can if desiredcontain flavourings and sweeteners. For external application thesubstances I according to the invention can also be used in the form ofpowders and ointments. For this they are for example mixed withphysiologically tolerated diluents in the form of powders orconventional ointment bases. The administered dose depends on the age,health and weight of the recipient, the extent of the diseases, the typeof additional treatments that may be carried out simultaneously, thefrequency of treatments and the type of desired effect. The daily doseis usually 0.1 to 50 mg/kg body weight of active compound. 0.5 to 40 andpreferably 1.0 to 20 mg/kg/day in one or several administrations per dayare generally effective in order to obtain the desired results.

The following compounds are preferred within the sense of the inventionapart from the substances stated in the examples:

6,7-dihydroxycoumarin-4-acetic acid yield 35%, melting point 210°-212°C. (water)!

6,7-dihydroxy-4-(2-hydroxy-ethyl)coumarin

3-(6,7-dihydroxycoumarin-4-yl)propionic acid

6,7-dihydroxy-4-(2,3-dihydroxy-propoxy)methylcoumarin

3-(2-oxo-2H-pyrano 3,2-g!quinoline-4-yl-methyl-mercapto) propionic acid

3-(6-hydroxy-3-oxo-3,7,8,9-tetrahydro-cyclopenta f!1!benzopyran-1-yl-methylmercapto)propionic acid

3-(6-hydroxy-3-oxo-7,8,9,10-tetrahydro-3H-naphtho2,1-b!pyran-1-yl-methylmercapto)propionic acid

3-(6-hydroxy-3-oxo-3H-naphtho 2,1-b!pyran-1-yl-methylmercapto)propionicacid

3-(5-allyl-6-hydroxy-3-oxo-3H-naphtho 2,1-b!pyran-1-yl-methylmercapto)propionic acid

3-(6-hydroxy-3-oxo-5-propyl-3H-naphtho 2,1-b!pyran-1-yl-methylmercapto)propionic acid

3-(1,2-dihydro-2-oxo-quinoline-4-yl-methylmercapto)- propionic acid

EXAMPLE 1

4-methy1-6,7-dihydroxycoumarin

45 ml 75% sulphuric acid is added dropwise to a mixture of 5.8 ml ethylacetate and 11.4 g 1,2,4-triacetoxy- benzene, heated for 30 min to 80°C., poured onto ice, filtered, the precipitate is washed neutral anddried in a vacuum. 8.2 g of the title compound (95 % of theory) isobtained with a melting point of 270° to 272° C.

EXAMPLE 2

In an analogous manner to that described in example 1 one obtains:

    ______________________________________                                                                        Melting                                                                Yield  point °C                               Name                     %      (solvent)                                     ______________________________________                                        a)  4-chloromethyl-6,7-dihydroxycoumarin from                                                              81     262                                           1,2,4-triacetoxy-benzene and    (ethanol)                                     4-chloroacetoacetic ester                                                 b)  4-bromomethyl-6,7-dihydroxycoumarin from                                                               62     246-248                                       1,2,4-triacetoxybenzene and     (ethanol)                                     4-bromoacetoacetic ester                                                  c)  4-(2-carboxy-phenylthio)methyI-6,7-                                                                    52     275-277                                       dihydroxycoumarin from 1,2,4-triacetoxybenzene                                                                (methanol)                                    and 4-(2-carboxy-phenylthio)aceto-                                            acetic ester                                                              d)  4-bromomethyl-7-methoxycoumarin                                                                        47     205-207                                       from 3-methoxy-phenol           (ether)                                       and 4-bromoacetoacetic ester                                              e)  4-bromomethyl-6-methoxycoumarin                                                                        45     169-171                                       from 4-methoxy-phenol           (ether)                                       and 4-bromoacetoacetic ester                                              f)  4-bromomethyl-6,7-methylenedioxycoumarin                                                               53     240-242                                       from 3,4-methylenedioxyphenol and                                                                             (methanol)                                    4-bromoacetoacetic ester                                                  ______________________________________                                    

EXAMPLE 3

4-N,N-dimethylaminomethy1-6,7-dihydroxycoumarin

5.7 g of the compound of example 2a is added to a solution of 4.5 gdimethylamine in 300 ml methanol, stirred overnight at room temperature,filtered, concentrated by evaporation and chromatographed on silica gel(eluting agent ethyl acetate: methanol 9:1). 3.3 g of the title compoundis isolated (56% of theory) with a melting point of 212° to 215° C.

EXAMPLE 4

In an analogous way to that described in example 3 one obtains:

    ______________________________________                                                                      Melting                                                                Yield  point °C                                 Name                   %      (solvent)                                       ______________________________________                                        a)  4-piperidinomethyl-6,7-                                                                              58     190-192                                         dihydroxycoumarinhydrochloride                                                                              (acetone)                                       from the compound example 2a                                                  and piperidine                                                            b)  4-morpholinomethyl-6,7-                                                                              67     above 270                                       dihydroxycoumarinhydrochloride                                                                              (ethanol)                                       from the compound example 2a                                                  and morpholine                                                            c)  4-(4-methoxy-piperidino)methyl-6,7-                                                                  48     232-234                                         dihydroxycoumarin hydrochloride from                                                                        (ethnol)                                        the compound example 2a and                                                   4-methoxy-piperidine                                                      d)  4-(2-carboxy-phenylthio)methyl-6,7-                                                                  45     275-277                                         dihydroxycoumarin from the compound                                                                         (ethanol)                                       example 2a and thiosalicylic acid                                         e)  4-(ethoxycarbonylmethylthio)methyl-6,7-                                                              64     oil                                             dihydroxycoumarin from the compound                                           example 2a and mercaptoacetic acid                                            ethyl ester                                                               f)  4-(2-ethoxycarbonyl-ethylthio)methyl-                                                                58     oil                                             6,7-dihydroxycoumarin                                                         from the compound example 2a and                                              3-mercaptopropionic                                                           acid ethyl ester                                                          g)  4-(4-methoxy-piperidino)methyl-7-                                                                    81     151-153                                         hydroxycoumarin from the      (ether)                                         compound example 8 and                                                        4-methoxypiperidine                                                       h)  4-(e-carboxy-phenylthio)methyl-                                               6,7-dihydroxycoumarin from                                                    the compound example 2a and                                                   3-mercaptobenzoic acid                                                    i)  4-(4-carboxy-phenylthio)methyl-                                               6,7-dihydroxycoumarin from                                                    the compound example 2a and                                                   4-mercaptobenzoic acid                                                    j)  4-(2-carboxy-phenylthio)methyl-                                                                      52     262-264                                         6-hydroxycoumarin                                                             from the compound example 7 and                                                                             (methanol)                                      thiosalicylic acid                                                        k)  4-(2-carboxy-phenylthio)methyl-7-                                                                    89     136-138                                         hydrocoumarin from the compound of                                                                          (water)                                         example 8 and thiosalicylic acid                                          i)  4-(2-carboxy-phenylthio)methyl-7-                                                                    45     238-240                                         hydrocoumarin from the compound of                                                                          (ethyl acetate)                                 example 2d and thiosalicylic acid                                         m)  4-(2-carboxy-phenylthio)methyl-                                               6,7-methylenedioxy coumarin from                                              the compound example 2f and                                                   thiosalicylic acid                                                        n)  4-(2-carboxy-phenoxy)methyl-6,7-                                              dihydroxycoumarin from                                                        the compound example 2a                                                       and salicylic acid                                                        o)  4-(2,6-dicarboxy-phenylthio)methyl-                                           6,7-dihydroxycoumarin                                                         from the compound example 2a                                                  and 2-mercapto-isophthalic acid                                           p)  4-aminomethyl-6,7-dihydroxycoumarin                                           from the compound                                                             example 2a and ammonia                                                    q)  4-(2-carboxy-anilino)methyl-6,7-                                              dihydroxycoumarin from                                                        example 2a and anthranilic acid                                           r)  4-(3-carboxy-anilino)methyl-6,7-                                              dihydroxycoumarin from                                                        example 2a and 3-amino-benzoic acid                                       s)  4-(4-carboxy-anilino)methyl-6,7-                                              dihydroxycoumarin from                                                        example 2a and 4-amino-benzoic acid                                       t)  4-hydroxymethyl-6,7-dihydroxycoumarin                                                                15     229-232                                         from the compound             (water)                                         example 2a and water                                                      u)  4-cyanomethyl-6,7-dihydroxycoumarin                                                                  43     129-131                                         from the compound             (ether)                                         example 2a and sodium cyanide                                             v)  2-(6,7-dihydroxycoumarin-4-yl-                                                                       58     208-210                                         methylmercapto)ethanol from   (ether)                                         the compound example 2a and                                                   2-mercapto-ethanol                                                        w)  (L)-S-(6,l-dihydroxycoumarin-4-yl-                                                                   66     182-184                                         methyl)cysteine from the      (water)                                         compound example 2a and (L)-cysteine                                      x)  4-(6,7-dihydroxycoumarin-4-yl-methyl-                                                                34     163-165                                         mercapto)butyric acid         (ethyl acetate)                                 from the compound example 2a and                                              4-mercapto-butyric acid                                                   y)  4-(2-hydroxy-ethylamino)methyl-6,7-                                                                  34     225-227                                         dihydroxycoumarin hydrochloride from                                                                        (acetone)                                       the compound example 2a and ethanolamine                                  z)  4-(2-amino-ethylamino)methyl-6,7-                                                                    47     208-210                                         dihydroxycoumarin hydrochloride from the                                                                    (water)                                         compound example 2a and ethylene-diamine                                  aa) 4-n-butylaminomathyl-6,7-                                                                            28     218-220                                         dihydroxycoumarin dihydroxychloride from                                                                    (acetone)                                       the compound example 2a and n-butylamine                                  ab) 4-N,N-diethylaminomethyl-6,7-                                                                        38     228-228                                         dihydroxycoumarin hydrochloride from                                                                        (acetone)                                       the compound example 2a and diethylamine                                  ac) 4-(4-oxo-piperidino)methyl-6,7-                                                                      55     233-235                                         dihydroxycoumarin hydrochloride from                                                                        (water)                                         the compound example 2a and 8-aza-                                            1,4-dioxaspiro 4,5!decane                                                 ad) 4-( 1-hydroxy-2-hexyl!amino)methyl-                                                                  17     200-202                                         6,7-dihydroxycoumarin hydrochloride from                                                                    (acetone)                                       the compound 2a and DL-2-amino-1-hexanol                                  ______________________________________                                    

EXAMPLE 5

6,7-dihydroxycoumarin-4-yl-methylmercaptoacetic acid

A mixture of 3.1 g of the compound of example 4e and 300 ml 50% aceticacid is heated for 24 hours to reflux. It is concentrated in a vacuum,taken up in diluted sodium bicarbonate solution, washed with ethylacetate, the aqueous phase is acidified and the product is filtered. 2.1g title compound (74% of theory) remains with a melting point of254°-256° C.

EXAMPLE 6

In an analogous manner to that described in example 5 one obtains:

    ______________________________________                                                               Yield  Melt. point °C                           Name                   %      (solvent)                                       ______________________________________                                        a)  3-(6,7-dihydroxycoumarin-4-                                                                          72     234-236                                         yl-methylmercapto)propionic   (water)                                         acid from the compound of example 4f                                      ______________________________________                                    

EXAMPLE 7

4-Bromomethyl-6-hydroxycoumarin

A mixture of 2.7 g of the compound of example 2e, 100 ml dichloromethaneand 5.6 ml boron tribromide is stirred for 4 hours at room temperature,poured onto ice and the product is filtered. 1.8 g title compound (71%of theory) with a melting point of 198° to 200° C. is isolated.

EXAMPLE 8

4-Bromomethyl-7-hydroxycoumarin is obtained from the compound of example2d analogously to example 7 in a yield of 70% and with a melting pointof 182° to 184° C.

EXAMPLE 9

6,7-Diacetoxy-4-(4-methoxy-piperidino)methylcoumarin hydrochloride

A mixture of 1.5 g of the compound of example 4c and 15 ml aceticanhydride is heated for 2 hours to reflux. It is concentrated byevaporation, triturated with ether and the product is filtered. 1.4 gtitle compound (75%) with a melting point of 206° to 208° C. remains.

EXAMPLE 10

6,7-Dimethoxy-4-(4-methoxy-piperidino)methylcoumarin

1.1 ml dimethylsulfate is added to a solution of 1.5 g of the compoundexample 4c in 6 ml 2N sodium hydroxide solution and it is stirredovernight at room temperature. It is extracted with dichloromethane,dried and the extract is concentrated. 0.44 g of the title compound (30%of theory) remains with a melting point of 148° to 150° C.

EXAMPLE 11

8-(4-methoxy-piperidino)methyl-2-thioxo-1,3-dioxolo 4,5-g!coumarin

5 ml pyridine is added to a mixture of 1.5 g of the compound of example4c and 40 ml chloroform and 1.12 ml thiophosgene dissolved in 10 mlchloroform is added dropwise at 20° C. It is stirred overnight at roomtemperature, the solution is washed with water, the organic phase isdried and purified on silica gel. 1.5 g of the title compound (88% oftheory) is eluted with ethyl acetate which melts at 108° to 110° C.after trituration with ether.

EXAMPLE 12

4-(2-Carboxy-phenylthio)methyl-6,7-diacetoxycoumarin with a meltingpoint of 216°-218° C. (ethyl acetate) is obtained in an analogous mannerto that described in example 9 from the compound of example 2c in a 68%yield.

EXAMPLE 13

4-(2-Carboxy-phenylthio)methyl-6,7-dimethoxycoumarin is obtained in a 45% yield from the compound of example 2c in an analogous manner to thatdescribed in example 10.

EXAMPLE 14

4-(2-Carboxy-phenylthio)methyl-6,7-ethylene-dioxycoumarin is obtainedfrom the compound of example 2c and 1,2-dibromoethane in an analogousmanner to that described in example 10.

Pharmacological tests

Effects of coumarins

The present application concerns pharmacological agents for thetreatment of acute and chronic diseases with an inflammatory,immunological, allergic, non-allergic or traumatic genesis.

Since phospholipase A₂ (PLA₂) is a key enzyme in the development ofthese diseases, its inhibition is an effective remedy for thesediseases.

Coumarins are inhibitors of PLA₂ whose profile of action is superior tothat of the introduced antiphlogistic agents such as e.g.cyclooxygenease inhibitors. In order to compare the profiles of actionindomethacin was selected as a typical cyclooxygenase inhibitor. Thedecrease of enzymatic activity measured as the cleavage of fatty acidsfrom the sn-2 position of lecithin was measured as an indicator of PLA₂inhibition.

Inhibition of PLA₂ activity

Human recombinant type II PLA₂ (=synovial PLA₂) was used for the testsas a typical representative of a PLA₂.

Table 1 shows the in vitro inhibition of this enzyme in percent by therepresentative compounds example 4c), example 5 and example 4w). Theenzyme was inhibited dose-dependently up to 100%.

In contrast table 1 shows that indomethacin also inhibited the enzymebut only to a maximum of 52% at the highest concentration. Thisdocuments the superiority of the new sPLA₂ inhibitors compared tocyclooxygenase inhibitors.

                  TABLE 1                                                         ______________________________________                                        Inhibition of sPLA.sub.2 enzyme activity by                                   coumarin derivatives and indomethacin                                                Substances                                                             Concentration                                                                          examp. 4c)                                                                              examp. 5 examp. 4w)                                                                            indomethacin                              ______________________________________                                        100 μg/ml                                                                           86        n.d.     n.d.    52                                         10 μg/ml                                                                           89        97       95      10                                         1 μg/ml                                                                            34        49       37       0                                        0.1 μg/ml                                                                            6         9        4      n.d.                                      ______________________________________                                         Mean values from 4 experiments (duplicate determinations), n.d. = not         determined                                                               

Conclusion

The lower inhibition of human recombinant type II PLA₂ by indomethacinillustrates that this cyclooxygenase inhibitor only has a weakinhibitory action on PLA₂. In contrast the coumarin representativesexamp. 4c), examp. 5 and examp. 4w) inhibited PLA₂ dose-dependently byup to 100% and are superior to introduced anti-inflammatory agents.

We claim:
 1. A method of inhibiting PLA₂ in a patient in need of suchinhibition, comprising administering to the patient an effective amountof a compound of the formula ##STR6## wherein R₁ is hydrogen,R₂ is aresidue OT₁, R₃ is a residue OT₂, R₄ is hydrogen, T₁ and T₂ areindependently hydrogen, C₁ -C₆ alkyl or C₁ -C₆ alkanoyl, or T₁ and T₂,together with the atoms to which they are bound, form a 5- to 7-memberedheterocyclic ring which is unsubstituted or is substituted by oxo orthioxo, Q is an oxygen atom, X is a sulfur atom or a NH group, Y is (a)a C₁ -C₆ alkylene residue which is unsubstituted or is a substituted bya hydroxyl group or an amino group, or (b) a phenylene residue which isunsubstituted or is substituted at least once by hydroxyl, halogen, C₁-C₆ alkyl or carboxyl, Z is halogen, carboxyl, hydroxymethyl, C₁ -C₆alkoxycarbonyl, cyano or a group NR₅ R₆ whereinR₅ and R₆ areindependently hydrogen or C₁ -C₆ alkyl, or R₅ and R₆, together with thenitrogen atom to whyich they are attached, form a 3- to 7-memberedheterocyclic ring which is unsubstituted or is substituted by oxo,hydroxy or C₁ -C₆ alkoxy, or a tautomer thereof or a salt thereof with anon-toxic acid or base.
 2. The method of claim 1, wherein the compoundis selected from the group consistingof(L)-S-(6,7-dihydroxycoumadn-4-yl-methyl) cysteine,4-(4-methoxy-piperidino) methyl-6,7-dihydroxycoumarin and6,7-dihydroxycoumarin-4-yl-methylmercapto acetic acid.
 3. A compound ofthe formula ##STR7## wherein R₁ is hydrogen,R₂ is a residue OT₁, R₃ is aresidue OT₂, R₄ is hydrogen, T₁ and T₂ are independently hydrogen, C₁-C₆ alkyl or C₁ -C₆ alkanoyl, or T₁ and T₂, together with the atoms towhich they are bound, form a 5- to 7-membered heterocyclic ring which isunsubstituted or is substituted by oxo or thioxo, Q is an oxygen atom, Xis a sulfur atom, Y is (a) a C₁ -C₆ alkylene residue which isunsubstituted or is a substituted by a hydroxyl group or an amino group,or (b) a phenylene residue which is unsubstituted or is substituted atleast once by hydroxyl, halogen, C₁ -C₆ alkyl or carboxyl, Z iscarboxyl, hydroxymethlyl or C₁ -C₆ alkoxycarbonyl, or a tautomer thereofor a salt thereof with a non-toxic acid or base.
 4. The compound ofclaim 3, wherein the compound is selected from the group consistingof(L)-S-(6,7-dihydroxycoumarin-4-yl-methyl) cysteine and7-dihydroxycoumarin-4-yl-methylmercapto acetic acid. 5.4-(4-methoxy-piperidino) methyl-6, 7-dihydroxycoumarin, or a tautomerthereof or a salt thereof with a non-toxic acid or base.
 6. Apharmaceutical composition suitable for the inhibition of PLA₂,comprising a compound of the formula ##STR8## wherein R₁ is hydrogen,R₂is a residue OT₁, R₃ is a residue OT₂, R₄ is hydrogen, T₁ and T₂ areindependently hydrogen, C₁ -C₆ alkyl or C₁ -C₆ alkanoyl, or T₁ and T₂together with the atoms to which they are bound, form a 5- to 7-memberedheterocyclic ring which is unsubstituted or is substituted by oxo orthioxo, Q is an oxygen atom, X is a sulfur atom, Y is (a) a C₁ -C₆alkylene residue which is unsubstituted or is a substituted by ahydroxyl group or an amino group, or (b) a phenylene residue which isunsubstituted or is substituted at least once by hydroxyl, halogen, C₁-C₆ alkyl or carboxyl, Z is carboxyl, hydroxymethyl or C₁ -C₆alkoxycarbonyl, or a tautomer thereof or a salt thereof with a non-toxicacid or base, and a pharmaceutically acceptable carrier.
 7. Thepharmaceutical composition as claimed in claim 6, wherein the compoundis selected from the group consisting(L)-S-(6,7-dihydroxycoumarin-4-yl-methyl) cysteine and 6,7-dihydroxycoumarin-4-yl-methylmercapto acetic acid.
 8. A pharmaceuticalcomposition suitable for the inhibition of PLA₂, comprising4-(4-methoxy-piperidino) methyl-6, 7-dihydroxycoumarin, or a tautomerthereof or a salt thereof with a non-toxic acid or base, and apharmaceutically acceptable carrier.